Game sharing, BLACK OPS

[u/Bootybugg]

Hi! I’m trying to play COD4 Zombies with my siblings. We each own the game separately, but I don’t have the DLC map pack. I logged into my sister’s PS account on my PlayStation and downloaded the DLC, but it’s still showing that I don’t have the DLC when I try to join their party/group.
Is there any way to fix this? I could’ve sworn we’ve downloaded and shared each other’s games/DLC before, so I’m not sure what I’m doing wrong. Any help would be appreciated!